Polyarylether ketone imide adhesives

ABSTRACT

Aspects of the present disclosure generally describe polyarylether ketones and methods of use. In some aspects, a composition includes one or more polymers of formula (IV):

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/023,171 filed Jun. 29, 2018, which has issued as U.S. Pat. No.10,465,046 on Nov. 5, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/068,249 filed Mar. 11, 2016, which has issued asU.S. Pat. No. 10,011,685 on Jul. 3, 2018. The above-referencedapplications are hereby incorporated by reference in their entirety.

FIELD

Aspects of the present disclosure generally relate to polyaryletherketones and methods of use.

BACKGROUND

A vehicle, such as an aircraft, contains many components adhered to oneanother by adhesives and/or fasteners. Adhesives and fasteners mustwithstand chemical, thermal, and physical conditions experienced by thevehicle. Adhesives offer greater performance, better design efficiency,and lower weight as compared to fasteners used for connecting thevehicle/aircraft components to one another. In particular, thermosetschemically or physically join vehicle/aircraft components by co-cure orco-bonding processes. However, co-curing involves expensive, precisiontooling to properly locate and maintain the vehicle components as wellas control of the thermoset resin distribution throughout the curingprocess. Additionally, co-cured structures typically suffer thicknesscontrol issues and ply waviness due to undesirable viscosity of anadhesive. Alternatively, co-bonding involves less extensive tooling butadds the costly labor of surface preparation for the surfaces of thevehicle components to be joined.

Regarding thermoset materials, thermosets have components that aretypically fabricated with a peel ply on the surfaces to be joined, whichis removed prior to joining, coupled with a surface preparation processsuch as grit blasting, plasma etching, and or hand sanding of thesurfaces to be joined, and followed by bonding of those surfaces with anadhesive. Adhesives are typically thermosets or thermoplastics, such aspoly ether ketone ketone (PEKK) or poly ether ether ketone (PEEK).However, thermoplastics are inherently more difficult for adhesivebonding applications in comparison to thermosets due to the chemicalnature of poly aryl ether ketone matrix, and their associated processingtemperatures when used in structural applications.

Low cost thermoplastics for film joining (adhesion) processes forvehicle components typically employ a melting/fused joining rather thana curing adhesive system. Ideal processing parameters for such athermoplastic would include:

-   -   about 355° C.-385° C. maximum processing temperature for        thermoplastic co-consolidation without polymer degradation    -   Glass transition temperature below about 190° C. for joining        thermoset applications without degrading the thermoset        component(s)    -   Polymer that is at least partially amorphous so that crystal        formations do not inhibit molecular diffusion at a film to film        interface    -   Polymer should have environmental/chemical resistance equal to        or better than vehicle base structures (i.e., vehicle components        and, if present, other layers on the components)    -   Polymer molecular weight should be balanced to provide good        mechanical properties while providing rheological properties        that promote chain mobility close to the glass transition        temperature    -   Polymer should have adequate adhesion ability

Existing adhesives do not possess ideal properties. For example,existing materials do not have a low enough processing temperature forsuitable use with thermoset materials or the materials degrade at theprocessing temperature of thermoplastic composites. Polyether etherketone (PEEK) polymers, for example, have high strength, but processingtemperatures for PEEK polymers are high (generally above 355° C.).Furthermore, PEEK polymers are expensive and do not possess sufficientlyhigh Tg values for all applications.

There is a need in the art for polymers that may be used inthermoplastic prepregs/thermosets and/or as an adhesive invehicle/aircraft structures.

SUMMARY

In some aspects, a composition includes one or more polymers of formula(IV):

X is selected from

or combinations thereof. Z is selected from —H,

and combinations thereof, where R′ is selected from —H, halo, C1-C20alkyl, cyano, or combinations thereof.

R is selected from

or combinations thereof. L is selected from —CH₂—, —(CH₃)₂C—, —O—, —S—,—SO₂—, —CO—, or combinations thereof. Q is selected from —S—, —SO₂—,—(CF₃)₂C—, —O—, —(CH₃)₂C—, or combinations thereof. j is a positiveinteger, m is a positive integer, n is a positive integer, and q is apositive integer. The molecular weight of at least one of the one ormore polymers of formula (IV) is between about 50 kDa and about 150 kDa.

In some aspects, a composition includes one or more reaction productsof:

and at least one of

R is selected from

or combinations thereof. L is selected from —CH₂—, —(CH₃)₂C—, —O—, —S—,—SO₂—, —CO—, or combinations thereof. Q is selected from —S—, —SO₂—,—(CF₃)₂C—, —O—, —(CH₃)₂C—, or combinations thereof. j is a positiveinteger. The molecular weight of at least one of the one or morereaction products is between about 50 kDa and about 150 kDa.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toaspects, some of which are illustrated in the appended drawings. It isto be noted, however, that the appended drawings illustrate only typicalaspects of this present disclosure and are therefore not to beconsidered limiting of its scope, for the present disclosure may admitto other equally effective aspects.

FIG. 1 illustrates chemical structures of general Formula (I).

FIG. 2 illustrates chemical structures of general Formula (II).

FIG. 3 illustrates chemical structures of general Formula (III).

FIG. 4 illustrates chemical structures of general Formula (IV).

FIG. 5 is a schematic illustration of film consolidation on an adherend.

FIG. 6 is a schematic of a block copolymer and copolymer block-blockinteractions.

FIG. 7 is a graph illustrating load displacement curves of lap sheartesting of test coupons having the copolymers of Example 1 or Example 2.

FIG. 8 is a graph illustrating load displacement curves of lap sheartesting of test coupons having the copolymers of Example 4 or Example 5.

FIG. 9 is a graph illustrating storage moduli versus processingtemperatures of Example 1 and Example 5.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of one aspectmay be beneficially incorporated in other aspects without furtherrecitation.

DETAILED DESCRIPTION

The descriptions of the various aspects of the present disclosure havebeen presented for purposes of illustration, but are not intended to beexhaustive or limited to the aspects disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the described aspects.The terminology used herein was chosen to best explain the principles ofthe aspects, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the aspects disclosed herein.

Aspects of the present disclosure generally describe polyaryletherketones and methods of use.

In general, polyimides (not copolymers) have a solvent resistance thatis ideal, but processing temperatures are very high, which drasticallyincreases the cost of these polymers. Polyethersulfones (not copolymers)are generally tough polymers having very high Tg values, but poorchemical resistance. Thus, imide monomers of polymers of the presentdisclosure provide high Tg values, good solvent resistance, and thermalstability, while sulfone monomers of polymers of the present disclosureprovide high Tg values, overall durability, and thermal stability.

Imide monomers include ether imide ether imide ether (EIEIE) andderivatives thereof. In some aspects, EIEIE is of the general structure:

where R is selected from

and combinations thereof, where L is selected from —CH₂—, —(CH₃)₂C—,—O—, —S—, —SO₂— or —CO—, where Q is selected from —S—, —SO₂— or—(CF₃)₂C—, —O—, —(CH₃)₂C—, and where j is a positive integer. In someaspects, the molecular weight of the EIEIE does not exceed about 3 kDa.

Sulfone monomers include ether sulfone ether (ESE) and derivativesthereof. In some aspects, ESE is of the structure:

Ketone monomers include ether ketone ether (EKE) and derivativesthereof. In some aspects, EKE is of the structure:

An EKE monomer may be present in a polymer backbone as a majoritymonomer, which provides some processing improvements. For example, apolymer may comprise greater than about 33 mol % of EKE as compared toEIEIE and ESE. In other aspects, a polymer comprises greater than about50 mol % EKE as compared to EIEIE. Furthermore, in some aspects, theratio of EKE to EIEIE to ESE may be adjusted to optimize polymerproperties.

Furthermore, including isophthaloyl chloride (ICP) and terephthaloylchloride (TCP) for syntheses of polymers of the present disclosureprovides additional control of the crystallinity of the polymer, e.g.tailoring amorphous and crystalline blocks of a copolymer.

Isophthaloyl chloride (ICP):

Terephthaloyl chloride (TCP):

In some aspects, polymers of the present disclosure have Tg valuesbetween about 140° C. and about 225° C., for example about 140° C., 145°C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., or 180° C. Insome aspects, polymers of the present disclosure have Tm values betweenabout 200° C. and about 450° C., such as between about 330° C. and about355° C., for example about 330° C., 335° C., 340° C., 345° C., 350° C.,or 355° C. In some aspects, polymers of the present disclosure haveintrinsic viscosity values between about 1 and about 3, such as about1.5 and about 2.4, for example 1.5 or 2.4. In some aspects, polymers ofthe present disclosure have a molecular weight between about 10 kDa andabout 150 kDa, such as about 50 kDa and about 120 kDa, such as about 90kDa and about 110 kDa.

In some aspects, a composition includes one or more polymers of formulae(I), (II), or (III):

X is selected from

and combinations thereof. Y is selected from

and combinations thereof. In some aspects, a ratio

of is between about 1:1 and about 1:2.

Z is selected from —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R is selected from

and combinations thereof. L is selected from —CH₂—, —(CH₃)₂C—, —O—, —S—,—SO₂—, —CO—, and combinations thereof. Q is selected from —CH₂—, —S—,—SO₂— or —(CF₃)₂C—, —O—, —(CH₃)₂C—, and combinations thereof.

j is a positive integer, such as between about 1 and about 50, such asabout 1 and about 10. m is a positive integer, such as between about 1and about 200, such as about 1 and about 100. n is a positive integer,such as between about 1 and about 200, such as about 1 and about 100. pis a positive integer, such as between about 1 and about 200, such asabout 1 and about 100. q is a positive integer, such as between about 1and about 2,000, such as about 200 and about 1,000. In some aspects, aratio of m to n is between about 1:1 and about 1:2. A ratio of m to pmay be between about 1:1 and about 1:2, and a ratio of n to p may bebetween about 1:1 and about 1:2.

The molecular weight of the at least one of the one or more polymers offormulae (I), (II), or (III) may be between about 10 kDa and about 150kDa. In some aspects, the molecular weight of at least one of the one ormore polymers is between about 50 kDa and about 120 kDa. The molecularweight of at least one of the one or more polymers may be between about90 kDa and about 110 kDa.

In some aspects, the molecular weight of each moiety of the structure:

of formulae (I), (II), or (III) does not exceed about 3 kDa. In someaspects, the moiety:

is greater than about 33 mol % of the molecular weight of at least oneof the one or more polymers of formulae (I), (II), or (III). The moiety:

may be greater than about 50 mol % of at least one of the one or morepolymers.

In some aspects, a composition includes one or more polymers of formulae(I), (II), or (III) and has a glass transition temperature between about135° C. and about 225° C. A composition including one or more polymersof formulae (I), (II), or (III) may have a glass transition temperaturebetween about 135° C. and about 190° C., for example about 140° C., 145°C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., or 180° C. Acomposition including one or more polymers of formulae (I), (II), or(III) may have a melting temperature between about 200° C. and about450° C., for example about 330° C., 335° C., 340° C., 345° C., 350° C.,or 355° C.

In some aspects, at least one of the one or more polymers of formulae(I), (II), or (III) is a block copolymer. q may be 1, m may be aninteger between about 1 and about 1,000, such as about 1 and about 100,and n may be an integer between about 1 and about 1,000, such as about 1and about 100. In some aspects, at least one of the one or more polymersof formulae (I), (II), or (III) is a random copolymer. q may be aninteger between 2 and about 1,000, m may be an integer between about 1and about 100, and n may be an integer between about 1 and about 100.

In some aspects, a composition including at least one of the one or morepolymers of formulae (I), (II), or (III) further includes a fibermaterial. The fiber material comprises, for example, graphite,fiberglass, nylon, aramid polymers, spectra, and mixtures thereof.

As used herein, a vehicle component includes any component of a vehicle,such as a structural component such as a panel or joint of an aircraft,automobile, etc. In some aspects, a vehicle component includes acomposition having at least one of the one or more polymers of formulae(I), (II), or (III). The composition may have a glass transitiontemperature between about 135° C. and about 225° C., for example about140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C.,or 180° C., and a melting temperature between about 200° C. and about450° C., for example about 330° C., 335° C., 340° C., 345° C., 350° C.,or 355° C. The vehicle component may be a tail cone, a panel, a coatedlap joint between two or more panels, a wing-to-fuselage assembly,structural aircraft composite, fuselage body-joint and/or wingrib-to-skin joint.

In some aspects, a method includes using a composition having at leastone of the one or more polymers of formulae (I), (II), or (III) as anadhesive. The molecular weight of at least one of the one or morepolymers may be between about 10 kDa and about 150 kDa. In some aspects,a method includes coating a surface with a composition having at leastone of the one or more polymers of formulae (I), (II), or (III). Themolecular weight of at least one of the one or more polymers may bebetween about 10 kDa and about 150 kDa. The method may includecontacting the coated surface with a second surface and heating thecomposition to above about 355° C. The coated surface may include athermoplastic prepreg, thermoset prepreg, and/or metal. Heating thecomposition to above about 355° C. may consolidate the thermoplasticprepreg (or cure the thermoset prepreg). The second surface may includea thermoplastic prepreg, thermoset prepreg, and/or metal, and heatingthe composition to above about 355° C. may consolidate the thermoplasticprepreg (or cure the thermoset prepreg) of the first surface and thethermoplastic prepreg (or thermoset prepreg) of the second surface. Themethod may further include coating the second surface with a compositionhaving at least one of the one or more polymers of formulae (I), (II),or (III) to form a second coated surface. In some aspects, the firstsurface and the second surface is each a surface of a vehicle component.In some aspects, a method includes forming a three dimensional structureusing at least one of the one or more polymers of formulae (I), (II),and (III). One or more polymers of formulae (I), (II), and (III) may bedeposited onto a three dimensional structure using any suitabledeposition method including conventional 3D printing methods.Alternatively, at least a first part of a three dimensional structuremay be formed using the one or more polymers of formulae (I), (II), and(III). The three dimensional structure may further include areinforcement agent. The reinforcement agent may improve structuralintegrity of the three dimensional structure. The reinforcement agentmay be included in a mixture containing one or more polymers of formulae(I), (II), and (III) that is then deposited to form a three dimensionalstructure (or deposit a layer onto a three dimensional structure) usingany suitable deposition method such as a conventional 3D printingmethod. In some aspects, the reinforcement agent is selected from glass,carbon fibers, chopped carbon fibers, carbon black, and carbonnanotubes. The three dimensional structure may be formed using anysuitable 3D printing process, such as fused filament fabrication and/orselective laser sintering.

In some aspects, a composition includes one or more reaction productsof:

and at least one of

R is selected from

and combinations thereof. L is selected from —CH₂—, —(CH₃)₂C—, —O—, —S—,—SO₂—, —CO—, and combinations thereof. Q is selected from —S—, —SO₂—,—(CF₃)₂C—, —O—, —(CH₃)₂C—, and combinations thereof. j is a positiveinteger, such as between about 1 and about 100, such as between about 1and about 10. The molecular weight of at least one of the one or morereaction products is selected from between about 10 kDa and about 150kDa. In some aspects, the molecular weight of

does not exceed about 3 kDa.

In some aspects, a composition includes one or more polymers of formula(IV):

X is selected from

and combinations thereof. Z is selected from —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R is selected from

and combinations thereof.

L is selected from —CH₂—, —(CH₃)₂C—, —O—, —O—, —S—, —SO₂—, —CO—, andcombinations thereof. Q is selected from —S—, —SO₂—, —(CF₃)₂C—, —O—,—(CH₃)₂C—, and combinations thereof. j is a positive integer, such asbetween about 1 and about 100, such as about 1 and about 10. m is apositive integer such as between about 1 and about 1,000, such as about1 and about 100. n is a positive integer such as between about 1 andabout 1,000, such as about 1 and about 10. q is a positive integer suchas between about 1 and about 2,000, such as about 200 and about 1,000.In some aspects, a ratio of m to n is between about 1:1 and about 1:2. Aratio of

may be between about 1:1 and about 1:2.

In some aspects, the molecular weight of at least one of the one or morepolymers of formula (IV) is between about 50 kDa and about 150 kDa. Insome aspects, the molecular weight of at least one of the one or morepolymers of formula (IV) is between about 90 kDa and about 110 kDa.

In some aspects, the molecular weight of each moiety of the structure:

of formula (IV) does not exceed about 3 kDa. The moiety:

of formula (IV) may be greater than about 33 mol % of the molecularweight of at least one of the one or more polymers of formula (IV). Insome aspects, the moiety:

is greater than about 50 mol % of at least one of the one or morepolymers of formula (IV).

In some aspects, a composition including at least one of the one or morepolymers of formula (IV) has a glass transition temperature betweenabout 135° C. and about 225° C., for example about 140° C., 145° C.,150° C., 155° C., 160° C., 165° C., 170° C., 175° C., or 180° C. Acomposition having at least one of the one or more polymers of formula(IV) may have a glass transition temperature between about 135° C. andabout 190° C. and/or a melting temperature between about 200° C. andabout 450° C., for example about 330° C., 335° C., 340° C., 345° C.,350° C., or 355° C.

At least one of the one or more polymers of formula (IV) may be a blockcopolymer. In some aspects, q may be 1, m is an integer between about 1and about 1,000, such as about 1 and 100, and n is an integer betweenabout 1 and about 1,000, such as about 1 and about 100. At least one ofthe one or more polymers of formula (IV) may be a random copolymer. Insome aspects, q may be an integer between 2 and about 2,000, such asabout 2 and about 1,000. m is an integer between about 1 and about1,000, such as about 1 and about 100, and n is an integer between about1 and about 1,000, such as about 1 and about 100.

In some aspects, a composition includes at least one of the one or morepolymers of Formula (IV), where the moiety:

is about 17 mol % of the molecular weight of the polymer, R is

and j is 1. The moiety:

is about 32 mol % of the molecular weight of the polymer. X is

and X is about 46 mol % of the molecular weight of the polymer.

In some aspects, a composition includes at least one of the one or morepolymers of Formula (IV), where the moiety:

is about 23 mol % of the molecular weight of the polymer, R is

and j is 1. The moiety:

is about 29 mol % of the molecular weight of the polymer. The moiety:

is about 24 mol % of the molecular weight of the polymer, and themoiety:

is about 24 mol % of the molecular weight of the polymer.

In some aspects, a composition includes at least one of the one or morepolymers of Formula (IV) and a fiber material. The fiber material may begraphite, fiberglass, nylon, aramid polymers, spectra, and mixturesthereof.

In some aspects, a vehicle component includes a composition thatincludes at least one of the one or more polymers of Formula (IV). Thecomposition may have a glass transition temperature between about 135°C. and about 225° C., for example about 140° C., 145° C., 150° C., 155°C., 160° C., 165° C., 170° C., 175° C., or 180° C., and a meltingtemperature between about 200° C. and about 450° C., for example about330° C., 335° C., 340° C., 345° C., 350° C., or 355° C. The vehiclecomponent may be a tail cone, a panel, a coated lap joint between two ormore panels, a wing-to-fuselage assembly, structural aircraft composite,fuselage body-joint or wing rib-to-skin joint.

In some aspects, a method includes using a composition that includes atleast one of the one or more polymers of Formula (IV) as an adhesive. Amethod may include coating a surface with a composition having at leastone of the one or more polymers of Formula (IV). In some aspects, amethod includes coating a first surface with a composition that includesat least one of the one or more polymers of Formula (IV) to form acoated surface. The method includes contacting the coated surface with asecond surface and heating the composition to above about 355° C. Thefirst surface and/or the second surface may include a thermoplasticprepreg, thermoset prepreg, and/or metal. Heating the composition toabove about 355° C. may consolidate the thermoplastic prepreg (or curethe thermoset prepreg) of the first surface and/or, if present, thethermoplastic prepreg (or thermoset prepreg) of the second surface. Themethod may include coating the second surface with a composition thatincludes at least one of the one or more polymers of Formula (IV) toform a second coated surface. The first surface and/or the secondsurface may be a surface of a vehicle component. In some aspects, amethod includes forming a three dimensional structure using at least oneof the one or more polymers of formula (IV). One or more polymers offormula (IV) may be deposited onto a three dimensional structure usingany suitable deposition method including conventional 3D printingmethods. Alternatively, at least a first part of a three dimensionalstructure may be formed using the one or more polymers of formula (IV).The three dimensional structure may further include a reinforcementagent. The reinforcement agent may improve structural integrity of thethree dimensional structure. The reinforcement agent may be included ina mixture containing one or more polymers of formula (IV) that is thendeposited to form a three dimensional structure (or deposit a layer ontoa three dimensional structure) using any suitable deposition method suchas a conventional 3D printing method. In some aspects, the reinforcementagent is selected from glass, carbon fibers, chopped carbon fibers,carbon black, and carbon nanotubes. The three dimensional structure maybe formed using any suitable 3D printing process, such as fused filamentfabrication and/or selective laser sintering.

In some aspects, a composition includes one or more reaction productsof:

and at least one of

R is selected from

and combinations thereof. L is selected from —CH₂—, —(CH₃)₂C—, —O—, —S—,—SO₂—, —CO—, and combinations thereof. Q is selected from —S—, —SO₂—,—(CF₃)₂C—, —O—, —(CH₃)₂C—, and combinations thereof. j is a positiveinteger, such as between about 1 and about 100, such as about 1 andabout 10. The molecular weight of at least one of the one or morereaction products is between about 50 kDa and about 150 kDa. In someaspects, the molecular weight of

does not exceed about 3 kDa.

In some aspects, the one or more reaction products are formed from areaction mixture that includes

that is about 17 mol % of thereaction mixture, R is

and j is 1.

is about 32 mol % of the reaction mixture.

is about 46 mol % of the reaction mixture.

In some aspects, the one or more reaction products are formed from areaction mixture that includes

that is about 23 mol % of the reaction mixture, R is

and j is 1.

is about 29 mol % of the reaction mixture.

is about 24 mol % of the reaction mixture, and

is about 24 mol % of the reaction mixture.

Dynamic scanning calorimetry (DSC) may be used to determine glasstransition temperatures (Tg), melting temperatures (Tm), andcrystallization temperatures (Tc) of polymers of the present disclosure.Furthermore, thermal gravimetric analysis provides degradationtemperatures of the polymers.

Conditions for the DSC scans of the present disclosure: ASTM D3418 witha heating rate of 5° C. per minute. The sample is placed in a smallaluminum pan (approx. 5-10 milligram sample). The sample is heated to395° C. at 5° C./min. The sample is either (1) cooled at 5° C./min toroom temperature, or (2) quenched by removing the sample from the testchamber and placing the sample on a room temperature metal surface. Thesample is then heated again to 395° C. at 5° C./min.

Intrinsic viscosity may be used to determine the size of polymers (e.g.,molecular weight(s)) of polymers of the present disclosure. Intrinsicviscosity (IV) refers to the mean intrinsic viscosity as determined bydissolving about 0.1 g of polymer in about 100 mL of concentratedsulfuric acid at 25° C. method involves solubilizing the polymer insulfuric acid and then using an ubelode viscometer to determine theintrinsic viscosity.

Molecular weight of a composition of polymers is usually expressed interms of a moment of the molecular weight distribution of the polymermixture, defined as

${M_{z} = \frac{\sum{m_{i}^{z}n_{i}}}{\sum{m_{i}^{z - 1}n_{i}}}},$where m_(i) is the molecular weight of the ith type of polymer moleculein the mixture, and n_(i) is the number of molecules of the ith type inthe mixture. M₁ is also commonly referred to as M_(n), the “numberaverage molecular weight”. M₂ is also commonly referred to as M_(w), the“weight average molecular weight”. The compositions of polymers of thepresent disclosure may have M_(n) and/or M_(w) of between about 10 kDaand about 150 kDa, such as about 50 kDa and about 120 kDa, such as about90 kDa and about 110 kDa.

Molecular weight distribution of a composition of polymers may beindicated by a polydispersity ratio P_(Z), which may be defined as

${P_{z} = \frac{M_{z + 1}}{M_{z}}},$where M_(Z) is defined above. Polymer compositions of the presentdisclosure typically come from polymer mixtures having a polydispersityratio P_(Z) of between about 1 and about 3, for example about 2.

FIG. 1 illustrates chemical structures of general Formula (I). As shownin FIG. 1, polymers of the present disclosure include polymers ofFormula (I):

where X may be

and combinations thereof. Y may be

and combinations thereof. In some aspects, a ratio of

is between about 1:1 and about 1:2.

Z may be —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R may be selected from

and combinations thereof. L may be —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂—,—CO—, and combinations thereof. Q may be —S—, —SO₂— or —(CF₃)₂C—, —O—,—(CH₃)₂C—, and combinations thereof.

j is a positive integer, such as between about 1 and about 100, such asabout 1 and about 10. m is a positive integer, such as between about 1and about 1,000, such as about 1 and about 100. n is a positive integer,such as between about 1 and about 1,000, such as about 1 and about 10. pis a positive integer, such as between about 1 and about 1,000, such asabout 1 and about 100. q is a positive integer, such as between about 1and about 2,000, such as about 200 and about 1,000.

In some aspects, a ratio of m to n values of Formula (I) is betweenabout 0.1:10 and about 10:0.1, such as about 1:1 and about 1:2. A ratioof m to p values of Formula (I) may be between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2. A ratio of n to p values ofFormula (I) may be between about 0.1:10 and about 10:0.1, such as about1:1 and about 1:2. In some aspects, a ratio of

(for X and Y moieties of Formula (I)) is between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2.

FIG. 2 illustrates chemical structures of general Formula (II). As shownin FIG. 2, polymers of the present disclosure further include polymersof formula (II):

where X may be

and combinations thereof. Y may be

and combinations thereof. In some aspects, a ratio of

is between about 1:1 and about 1:2.

Z may be —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R may be selected from

and combinations thereof. L may be —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂—,—CO—, and combinations thereof. Q may be —S—, —SO₂— or —(CF₃)₂C—, —O—,—(CH₃)₂C—, and combinations thereof.

j is a positive integer, such as between about 1 and about 100, such asabout 1 and about 10. m is a positive integer, such as between about 1and about 1,000, such as about 1 and about 100. n is a positive integer,such as between about 1 and about 1,000, such as about 1 and about 10. pis a positive integer, such as between about 1 and about 1,000, such asabout 1 and about 100. q is a positive integer, such as between about 1and about 2,000, such as about 200 and about 1,000.

In some aspects, a ratio of m to n values of Formula (II) is betweenabout 0.1:10 and about 10:0.1, such as about 1:1 and about 1:2. A ratioof m to p values of Formula (II) may be between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2. A ratio of n to p values ofFormula (II) may be between about 0.1:10 and about 10:0.1, such as about1:1 and about 1:2. In some aspects, a ratio of

(for X and Y moieties of Formula (II)) is between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2.

FIG. 3 illustrates chemical structures of general Formula (III). Asshown in FIG. 3, polymers of the present disclosure further includepolymers of formula (III):

where X may be

and combinations thereof. Y may be

and combinations thereof. In some aspects, a ratio of

is between about 1:1 and about 1:2.

Z may be —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R may be selected from

and combinations thereof. L may be —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂—,—CO—, and combinations thereof. Q may be —S—, —SO₂— or —(CF₃)₂C—, —O—,—(CH₃)₂C—, and combinations thereof.

j is a positive integer, such as between about 1 and about 100, such asabout 1 and about 10. m is a positive integer, such as between about 1and about 1,000, such as about 1 and about 100. n is a positive integer,such as between about 1 and about 1,000, such as about 1 and about 100.p is a positive integer, such as between about 1 and about 1,000, suchas about 1 and about 100. q is a positive integer, such as between about1 and about 2,000, such as about 200 and about 1,000.

In some aspects, a ratio of m to n values of Formula (III) is betweenabout 0.1:10 and about 10:0.1, such as about 1:1 and about 1:2. A ratioof m to p values of Formula (III) may be between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2. A ratio of n top values ofFormula (III) may be between about 0.1:10 and about 10:0.1, such asabout 1:1 and about 1:2. In some aspects, a ratio of

(for X and Y moieties of Formula (III)) is between about 0.1:10 andabout 10:0.1, such as about 1:1 and about 1:2.

FIG. 4 illustrates chemical structures of general Formula (IV). As shownin FIG. 4, polymers of the present disclosure include polymers offormula (IV):

where X may be

and combinations thereof. Z may be —H,

and combinations thereof, where R′ is —H, halo, C1-C20 alkyl, cyano, orcombinations thereof.

R may be

and combinations thereof.L may be —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂—, —CO—, and combinationsthereof. Q may be —S—, —SO₂—, —SO₂—, —(CF₃)₂C—, —O—, —(CH₃)₂C—, andcombinations thereof. j is a positive integer, such as between about 1and about 100, such as about 1 and about 10. m is a positive integersuch as between about 1 and about 1,000, such as about 1 and about 100.n is a positive integer such as between about 1 and about 1,000, such asabout 1 and about 100. q is a positive integer such as between about 1and about 1,000, such as about 1 and about 100. The molecular weight ofthe polymer of formula (IV) may be between about 10 kDa and about 150kDa, such as about 50 kDa and about 120 kDa, such as about 80 kDa andabout 100 kDa.

In some aspects, a ratio of m to n values of Formula (IV) is betweenabout 0.1:10 and about 10:0.1, such as about 1:1 and about 1:2. In someaspects, a ratio of

(for X moieties of Formula (IV)) is between about 0.1:10 and about10:0.1, such as about 1:1 and about 1:2.

Polymer Syntheses

Polymers of the present disclosure, and synthesized from monomersdescribed above, may be random copolymers or block copolymers.

Random Copolymers:

Synthetic approaches for random copolymers include (1) electrophilicsyntheses, (2) nucleophilic syntheses, or (3) electrophilic gelsyntheses. In some aspects, an electrophilic gel synthesis involvescharging a reactor with about 788 g of aluminum chloride and about 50 mLdichloromethane, followed by cooling the mixture to −15° C. Next, about200 g of EKE monomer is dissolved in 25 mL dichloromethane and added tothe solution containing aluminum chloride to form a reaction mixture.Then, about 190 g of EIEIE monomer dissolved in 50 mL of dichloromethaneis added to the reaction mixture. Next, about 160 g of TCP/ICP monomersin 25 mL dichloromethane is added to the reaction mixture. Then, about20 g of benzoyl chloride in 10 mL dichloromethane is added to the bulkreaction mixture, and the mixture is allowed to warm to about 10° C. andstirred for about 4.5 hours while maintaining temperature at 10° C. Thereaction mixture may then be washed using any suitable washing process,for example a hydrochloric acid wash. However, a gel process results ina gel having large amounts of hydrochloric acid, which leads todifficulties in scalability. Furthermore, reaction temperatures ofelectrophilic syntheses are typically lower than temperatures involvingnucleophilic reactions, making electrophilic syntheses more amenable toscale up.

Electrophilic syntheses may include Friedel Crafts synthesis in which anaryl ketone linkage is formed from a carboxylic acid halide and anaromatic compound having an activated hydrogen, i.e., a hydrogen atomdisplaceable under the electrophilic reaction conditions. The monomersystem employed in the reaction can be, for example, (a) a singlearomatic compound containing a carboxylic acid halide (e.g., a cappingagent) as well as an aromatic carbon bearing a hydrogen activatedtowards electrophilic substitution (e.g., EKE, EIEIE, or ESE); or (b) atwo-monomer system of a dicarboxylic acid dihalide (e.g., TCP or ICP)and an aromatic compound containing two such activated hydrogens (e.g.,EKE, EIEIE, or ESE). A reaction mixture for such Friedel Craftsreactions includes the monomers, a catalyst, such as anhydrous aluminumchloride, and an inert solvent such as methylene chloride.

In some aspects, copolymers of the present disclosure (both random andblock copolymers) are synthesized by Friedel Crafts reactions wherereaction conditions generally include adding TCP/ICP, EKE, ESE, andEIEIE to a reactor with o-dichlorobenzene, dichloromethane, and/ordichloroethane as a solvent. The solution may be cooled to about —10°C., and aluminum chloride added slowly over about 30 minutes. Followingaddition of the aluminum chloride, the reaction mixture may be allowedto warm to about 10° C., held at 10° C. for about 10 minutes, andre-cooled to —10° C. Additional TCP/ICP may then be added. Preheatedsolvent (for example, o-dichlorobenzene between about 160° C. and about190° C.) may then be added to the reaction mixture, and the reactionmixture may be held at 100° C. for at least about 30 minutes. In someaspects, the reaction mixture is then decomplexed using, for example,ice water. For every 1 kg of polymer, at least about 3 kg of water maybe used to rinse and neutralize the hydrochloric acid. The sample isthen dried. An additional 8 liters (L) of water (per 1 kg polymer) isthen added to the sample and heated to about 95° C. while stirring.Water is then removed (e.g., by distillation). An additional 8 liters(L) of water (per 1 kg polymer) is then added to the sample and againheated to about 95° C. while stirring. Water is then decanted. 8 L ofwater (per 1 kg polymer) and 200 mL of NH3 (per 1 kg polymer) is thenadded to the sample and heated to about 95° C. while stirring. Water isthen removed. 8 L of deionized water is then added to the sample andheated to about 95° C. while stirring. The sample is then dried at about120° C. for about 24 hours.

In some aspects, the temperature at which a Friedel Crafts reaction isconducted is between about —50° C. and about 160° C. The reaction maycommence at lower temperatures, for example between about —50° C. andabout —10° C. The temperature may then be raised if desired, up to about160° C. or even higher, for example, to promote the reaction tosubstantial completion. In some aspects, a Friedel Crafts reaction isperformed at temperatures in the range of between about —30° C. and 25°C. (e.g., room temperature).

In some aspects, one or more capping agents are added to a reactionmixture to cap the polymer on at least one end of the polymer backbone.Capping agents promote termination of continued growth of a polymerchain and control the resulting molecular weight of the polymer, asshown by the inherent viscosity of the polymer. Judicious use of thecapping agents results in a polymer within a controlled molecular weightrange, decreases gel formation during polymerization, decreasesbranching of the polymer chains, and increases melt stability. Molecularweights of polymers of the present disclosure are balanced to providegood mechanical properties while providing rheological properties thatpromote chain mobility close to the polymer glass transitiontemperatures.

In some aspects, capping agents are compounds of the formula:

where “Ar” includes phenyl or an aromatic group substituted with C1-C20alkyl and/or an electron withdrawing substituent such as halo or cyano,and E is halogen or other leaving group. Some exemplary capping agentsinclude benzoyl chloride, benzenesulfonyl chloride, 3-chlorophenyl,4-chlorophenyl, 4-cyanophenyl, 4-methylphenyl.

Decomplexation of the polymer from the aluminum chloride catalyst can beaccomplished by treating the reaction mixture with a decomplexing baseafter completion of polymerization. The base can be added to thereaction medium or the reaction medium can be added to the base. Thedecomplexing base may be at least as basic towards the Lewis acid(aluminum chloride) as the basic groups on the polymer chain. Suchdecomplexation may be performed before isolation of the polymer from thereaction mixture.

The amount of decomplexing base used may be in excess of the totalamount of bound (complexed) and unbound Lewis acid present in thereaction mixture and may be twice the total amount of Lewis acid.Decomplexing bases include water, dilute aqueous hydrochloric acid,methanol, ethanol, acetone, N,N-dimethyl-formamide,N,N-dimethylacetamide, pyridine, dimethyl ether, diethyl ether,tetrahydrofuran, trimethylamine, trimethylamine hydrochloride, dimethylsulfide, tetramethylenesulfone, benzophenone, tetramethylammoniumchloride, isopropanol and the like. The decomplexed polymer can then beremoved by adding a nonsolvent for the polymer which is a solvent for ormiscible with the Lewis acid/Lewis base complex and the Lewis acid;spraying the reaction mixture into a non-solvent for the polymer;separating the polymer by filtration; or evaporating the volatiles fromthe reaction mixture and then washing with an appropriate solvent toremove any remaining base/catalyst complex and diluent from the polymer.

Example of High Molecular Weight EIEIE+EKE+ESE Random CopolymerSynthesis:

2 L of cooled (e.g., −20° C.) dichloromethane (DCM) is added to areactor. Aluminum chloride (approx. 500 g) is dissolved in about 50 mLof additional chilled DCM. EKE monomer (about 150 g) is dissolved inabout 25 mL of chilled DCM. Dimethyl sulfone (about 100 g) is dissolvedin about 25 mL of DCM and chilled. EIEIE (approx. 100 g) and ESE(approx. 100 g) monomers is dissolved in DCM, chilled to, for example,−20° C., and added to the reactor. Terephthaloyl chloride and/orisophthaloyl chloride are dissolved in DCM, chilled, and added to thereactor. The temperature of the reaction mixture is increased slowly toabout 20° C. over a period of 4.5 hours and stirred continuously. Amolar excess of end cap, such as benzoyl chloride, is then added andstirring is continued at 20° C. for an additional 30 minutes. Thereaction is then quenched by adding 1 liter of methanol chilled to about−40° C. Stirring is continued for about an hour. The polymer is filteredand rewashed twice with one liter of methanol. The polymer istransferred to a beaker and boiled in one liter of water until theliquid temperature is about 98° C. After filtration, the polymer issoaked in about 500 g glacial formic acid for about 30 minutes, filteredand dried overnight in a vacuum oven at about 170° C. with a lightnitrogen bleed.

Example of High Molecular Weight EIEIE+EKE Random Copolymer Synthesis:

2 L of cooled (e.g., −20° C.) dichloromethane (DCM) is added to areactor. Aluminum chloride (about 500 g) is dissolved in about 50 mL ofadditional chilled dichloromethane. EKE monomer (about 150 g) isdissolved in about 25 mL of chilled DCM. Dimethyl sulfone (about 100 g)is dissolved in about 25 mL of DCM and chilled. EIEIE (about 100 g)monomer is dissolved in DCM, chilled to, for example, −20° C., and addedto the reactor. Terephthaloyl chloride and/or isophthaloyl chloride aredissolved in DCM, chilled, and added to the reactor. The temperature ofthe reaction mixture is increased slowly to about 20° C. over a periodof 4.5 hours and stirred continuously. A molar excess of end cap, suchas benzoyl chloride, is then added and stirring is continued at 20° C.for an additional 30 minutes. The reaction is then quenched by adding 1liter of methanol chilled to about −40° C. Stirring is continued forabout an hour. The polymer is filtered and rewashed twice with one literof methanol. The polymer is transferred to a beaker and boiled in oneliter of water until the liquid temperature is about 98° C. Afterfiltration, the polymer is soaked in about 500 g glacial formic acid forabout 30 minutes, filtered and dried overnight in a vacuum oven at about170° C. with a light nitrogen bleed.

Block Copolymers:

Block copolymers may be synthesized by: (1) sequential monomer additionor (2) macro-initiator methods. Specifically, sequential monomeraddition may involve a Friedel Crafts reaction, similar to thatdescribed above for random copolymer synthesis. However, reactionconditions of a Friedel Crafts reaction for polymer synthesis (asdescribed above) may be adjusted, e.g. order of addition of reagents,such that a block copolymer is formed instead of a random copolymer.

In addition, providing to a reaction mixture (1) ratios or sequentialaddition of ICP and TCP and/or (2) ratios or sequential addition ofEKE/EIEIE/ESE or EKE/EIEIE for syntheses of random and block copolymersof the present disclosure provides control of the crystallinity of thecopolymer, e.g. tailoring amorphous and crystalline blocks of a blockcopolymer. Thus, sequential monomer addition of (1) TCP or ICP and/or(2) EKE/EIEIE/ESE will promote block copolymers with controlledformation of crystalline or semicrystalline blocks and amorphous blocks.As indicated in the general description above of Formulae (I), (II),(III), and (IV), a particular ratio of EKE/EIEIE/ESE or EKE/EIEIEmonomers of a copolymer synthesis affects, for example, integer valuesof n, m, and p of Formulae (I), (II), (III), and (IV), and a particularratio of ICP/TCP monomers of a copolymer synthesis affects the identityand quantity of X and Y of Formulae (I), (II), (III), and (IV).

Example of High Molecular Weight EIEIE+EKE+ESE Block Copolymer:

2 L of cooled (e.g., −20° C.) dichloromethane (DCM) is added to areactor. Aluminum chloride (about 500 g) is dissolved in about 50 mL ofadditional chilled dichloromethane. A molar excess of EKE is dissolvedin about 25 mL of DCM and chilled to, for example, −20° C. The molarexcess of EKE ensures that the polymers formed in the first phase ofthis synthesis are low molecular weight polymers. The high molecularweight polymers are achieved by the end of the overall synthesis.Dimethyl sulfone is dissolved in DCM, chilled, and added to the reactor.EIEIE monomer is dissolved in DCM, chilled, and added to the reactor.Terephthaloyl chloride and/or isophthaloyl chloride are dissolved inDCM, chilled, and added to the reactor. The temperature of the reactionmixture is then increased to about 20° C. slowly over a period of about2 hours and stirred continuously. The reaction mixture is then cooled toabout −20° C. Additional EKE monomer is dissolved in DCM, chilled, andadded to the reactor. Additional ESE monomer is also dissolved in DCM,chilled, and added to the reactor. Terephthaloyl chloride and/orisophthaloyl chloride are dissolved in DCM, chilled, and added to thereactor. The temperature of the reaction mixture is increased to about20° C. slowly over a period of 4.5 hours and stirred continuously. Amolar excess of end capper, such as benzoyl chloride, is then added tothe reaction mixture and stirring is continued at about 20° C. for anadditional about 30 minutes. The reaction is then quenched by adding 1liter of methanol chilled to about −40° C. Stirring is continued forabout an hour. The polymer is filtered and rewashed twice with one literof methanol. The polymer is transferred to a beaker and boiled in oneliter of water until the liquid temperature is about 98° C. Afterfiltration, the polymer is soaked in about 500 g glacial formic acid forabout 30 minutes, filtered and dried overnight in a vacuum oven at about170° C. with a light nitrogen bleed.

Example of High Molecular Weight EIEIE+EKE Block Copolymer:

2 L of cooled (e.g., −20° C.) dichloromethane (DCM) is added to areactor. Aluminum chloride (about 500 g) is dissolved in about 50 mL ofadditional dichloromethane and chilled. A molar excess of EKE isdissolved in about 25 mL of DCM and chilled to, for example, −20° C. Themolar excess of EKE ensures that the polymers formed in the first phaseof this synthesis are low molecular weight polymers. The high molecularweight polymers are achieved by the end of the overall synthesis.Dimethyl sulfone is dissolved in DCM, chilled, and added to the reactor.EIEIE monomer is dissolved in DCM, chilled, and added to the reactor.Terephthaloyl chloride and/or isophthaloyl chloride are dissolved inDCM, chilled, and added to the reactor. The temperature of the reactionmixture is then increased to about 20° C. slowly over a period of about2 hours and stirred continuously. The reaction mixture is then cooled toabout −20° C. Additional EKE monomer is dissolved in DCM, chilled, andadded to the reactor. Additional EIEIE monomer is also dissolved in DCM,chilled, and added to the reactor. Terephthaloyl chloride and/orisophthaloyl chloride are dissolved in DCM, chilled, and added to thereactor. The temperature of the reaction mixture is increased to about20° C. slowly over a period of 4.5 hours and stirred continuously. Amolar excess of end capper, such as benzoyl chloride, is then added tothe reaction mixture and stirring is continued at about 20° C. for anadditional about 30 minutes. _The reaction is then quenched by adding 1liter of methanol chilled to about −40° C. Stirring is continued forabout an hour. The polymer is filtered and rewashed twice with one literof methanol. The polymer is transferred to a beaker and boiled in oneliter of water until the liquid temperature is about 98° C. Afterfiltration, the polymer is soaked in about 500 g glacial formic acid forabout 30 minutes, filtered and dried overnight in a vacuum oven at about170° C. with a light nitrogen bleed.

Polymer Applications

Non-limiting examples for uses of block copolymers and random copolymersof the present disclosure include uses as thermoplastic adhesives and asa component of prepreg material. For prepreg material, polymers of thepresent disclosure may be applied onto and/or impregnated into fibermaterials composed of graphite, fiberglass, nylon, Kevlar® and relatedmaterials (for example, other aramid polymers), spectra, among others.

High molecular weight block copolymers and random copolymers of thepresent disclosure, such as copolymers of Formulae (I), (II), (III), and(IV), have superior physical and chemical properties as compared toexisting thermoplastic polymer adhesives and prepreg polymers. Forexample, in some aspects, copolymers of Formulae (I), (II), (III), and(IV) undergo processing at temperatures of about 355° C. or 385° C.without polymer degradation. Furthermore, in some aspects, copolymers ofFormulae (I), (II), (III), and (IV) have glass transition temperaturesbelow about 190° C. for joining thermoset applications without degradingthe thermoset component. In addition, copolymers of Formulae (I), (II),(III), and (IV) may be at least partially amorphous so that crystalformations do not inhibit molecular diffusion at a film to filminterface. Copolymers of Formulae (I), (II), (III), and (IV) may alsohave environmental/chemical resistance equal to or better than basestructures (i.e., vehicle components and, if present, other typicallayers on the components). Furthermore, syntheses of the presentdisclosure for copolymers of Formulae (I), (II), (III), and (IV) allowcopolymer molecular weights that are high molecular weights, but arenonetheless balanced to provide good mechanical properties whileproviding rheological properties that promote chain mobility close tothe glass transition temperatures. Furthermore, the high molecularweights of copolymers of Formulae (I), (II), (III), and (IV) promoteadhesion ability with vehicle surfaces utilizing physical interactionswith the surface, instead of chemical reactions with the surface whichis typical for existing low molecular weight polymers.

Diffusion Bonded Adhesive that is a Random Copolymer:

Amorphous thermoplastic films (e.g., a composition comprising one ormore polymers of the present disclosure) may be used to jointhermoplastics to thermoplastics and thermoplastics to thermosets. Thefilm should be thermally stable at processing temperatures greater than355° C. and compatible with epoxies. An adherend (to which the film isapplied) may be a thermoset composite, thermoplastic composite, or ametal substrate.

FIG. 5 is a schematic illustration of film consolidation on an adherend.As shown in FIG. 5, stack 500 contains sheets 502 of thermoplasticprepreg. The sheets are not consolidated. Applying high heat (such as355° C.-385° C.) and pressure promotes consolidation of the stack toform consolidated thermoplastic composite 504. Temperatures andpressures for consolidating known thermoplastic polymers degrade thepolymers impregnated within and onto a prepreg. However, high molecularweight polymers of the present disclosure, such as polymers of Formulae(I), (II), (III), and (IV), provide temperature resistance at thetypical processing temperatures.

Also shown in FIG. 5, consolidated thermoplastic prepreg 504 can bejoined with a companion thermoplastic composite 506 using heat andpressure. The two or more thermoplastic prepregs may be alreadyconsolidated (e.g., consolidated thermoplastic prepreg 504) beforejoining of the two films. A random copolymer of Formulae (I), (II),(III), and/or (IV) is placed on a surface of consolidated thermoplasticprepreg 504 and/or a surface of companion thermoplastic composite 506.The surfaces are mated together by heating the structure with pressure,forming a bonded prepreg stack 508. High molecular weight polymers ofthe present disclosure are useful for these purposes because the highmolecular weight copolymers of Formulae (I), (II), (III), and/or (IV)promote adhesion without detrimentally high viscosity upon heating andincreased pressure. In general, polymer viscosity becomes unworkable ifthe molecular weight of a polymer becomes too large, furtherhighlighting an advantage of copolymers having high molecular weightsthat are balanced. Also, high molecular weight copolymers of Formulae(I), (II), (III), and/or (IV) utilize physical interactions with anadjacent surface to promote adhesion of adjacent surfaces, as opposed tochemical reactions with adjacent surfaces which is typical for known lowmolecular weight polymers.

In some aspects, one or both of the thermoplastic prepregs may beconsolidated simultaneously upon a film joining (a“co-consolidation”)(e.g, thermoplastic prepreg 504 and companionthermoplastic composite 506 are not yet consolidated upon film joining).Thus, the film joining process may also be a consolidation process.

Diffusion Bonded Adhesive that is a Block Copolymer:

Adhesion processes for block copolymers of the present disclosure arethe same as those with random copolymers, e.g. as shown in FIG. 5.However, in some aspects, the adhesion ability of a block copolymer maybe stronger than the adhesion ability of a corresponding randomcopolymer because the block copolymer provides a core block that isrelatively crystalline and one or more adjacent blocks that areamorphous. FIG. 6 is a schematic of a block copolymer and copolymerblock-block interactions. As shown in FIG. 6, a block copolymer 600 hasa crystalline core (block) 602 and amorphous arms (blocks) 604.Crystalline core 602 may be, for example, EIEIE monomeric unitsconnected by TCP or ICP linkers, while amorphous arms 604 may be, forexample, EKE monomeric units connected by TCP or ICP linkers. Afterprocessing, crystalline blocks of the block copolymer may be physicallyentangled with each other, such that there are now two types of physicalcross sections for polymer-polymer interactions: one type that iscrystalline-crystalline block interactions and one type that isamorphous-amorphous block interactions. For example, different moleculesof block copolymer 600 may form a copolymer aggregate 606, promoted bycrystalline-crystalline block interactions of crystalline core 602 ofmolecules of block copolymer 600. The crystalline-crystalline blockinteractions are high strength interactions. Furthermore, the one ormore amorphous blocks adjacent to a crystalline core provide a blockcopolymer that is at least partially amorphous so that crystalformations do not inhibit molecular diffusion at a film to filminterface, such as the interface of consolidated thermoplastic prepreg504 and companion thermoplastic composite 506 of FIG. 5.

Example Copolymers Examples

(as used herein, “% OOB” denotes the percent out of balancestoichiometry (ether/imide or ether/sulfone is in excess)). Target glasstransition temperatures (Tg) are greater than about 135° C. and targetmelting temperatures are less than about 355° C.

Benzoyl Chloride % Viscosity EIEIE EKE ESE TCP ICP End Cap OO Tg @ 380°C. ΔH_(c) Example (mol %) (mol %) (mol %) (mol %) (mol %) (mol %) B (°C.) (Pa × S) (J/g) 1 (High MW) 24.45 28.06 0 24.74 27.74 2 178 1840 2(Low MW) 22.61 28.26 0 24.56 24.56 3.5 174 165 3^(a) 16.92 32.01 0 45.580 5.48 169 29.8 4 (Low MW) 53.20 28.35 0 24.23 24.23 6 186 448 5 (HighMW) 23.44 28.65 0 23.96 23.96 8 187 1660 6 (High MW) 15 20 15 45 0 5 182a: Tg = 169° C. Tm = 212° C.

The polymers of Example 1 and Example 2 may be amorphous. Example 1 is acopolymer with a significantly lower Tg value (approx. 40° C.) thanPEKK, polyether imide (PEI), and polyethersulfone (PES), but maintainssimilar mechanical properties, has excellent thermal stability, and hasequivalent or improved miscibility with PEKK.

A small subset of three coupons was made for Example 1 and Example 2 inthe continuous compression molding (CCM) process and the autoclave at375° C. for 1 hour at 100 psi. The coupons were fabricated with polymer(Example 1 or Example 2) as a film that was converted from reactor flakein a press.

A continuous compression molding process was used to flatten the film(Example 1 or Example 2) to a uniform thickness onto co-consolidatedadherends. FIG. 7 is a graph illustrating load displacement curves oflap shear testing of test coupons including the copolymers of Example 1or Example 2. Lap shear strengths were measured from 0.5 square inchlaps. As shown in FIG. 7, lap shear strength of Example 1 (line 702) is7.1+/−1 thousands of pounds per square inch (ksi), while lap shearstrength of Example 2 (line 704) is 3.0+/−0.2 ksi, illustrating anadvantage of high molecular weight copolymers of the present disclosure.

Furthermore, comparison of failure modes between test coupons includingExample 1 and Example 2 show first ply failure (predominantly fiber tearfailure) for test coupons including Example 1, but adhesive failurebetween film-to-film layers for test coupons including Example 2.

The results of the lap shear tests are favorable for Example 1, thehigher molecular weight version of the co-polymer. In this case, polymerchain length of Example 2 was too small showing a failure between thetwo films (Example 2 had the lower viscosity at 380° C.).

Example 4 and Example 5 were fabricated in the same manner as Example 1and Example 2, but were joined in the autoclave at 190° C. due to theirslightly higher glass transition temperatures. FIG. 8 is a graphillustrating load displacement curves of lap shear testing of testcoupons including the copolymers of Example 4 or Example 5. Lap shearstrengths were measured from 0.5 square inch laps. As shown in FIG. 8,lap shear strength of Example 4 (line 802) is 7.0+/−0.7 ksi, while lapshear strength of Example 5 (line 804) is 7.2+/−0.5 ksi.

Again, the higher molecular weight version (Example 5) provided betterperformance over a lower molecular weight. However, only a smalldifference was observed in failure modes of Example 4 and Example 5, asboth examples have first ply failure in adherends. Shear strength ofimide-based co-polymers of the present disclosure are the highestrecorded in comparison to known films including pseudo amorphous PEKK-DSand PES.

FIG. 9 is a graph illustrating storage moduli versus processingtemperatures of Example 1 and Example 4. As shown in FIG. 9, Example 1(line 902) and Example 4 (line 904) each have a storage modulus (G′) ingigaPascals (GPa) that drastically declines at temperatures above 175°C., such as about 190° C. Thus, a temperature of about 190° C. isobtained for film joining with common thermoset matrix composites, andprovides a significantly lower processing temperature window as comparedto known film joining processes. (Example 5 gave very similar data asExample 4).

High molecular weight copolymers of the present disclosure provideimproved lap shear strength but are of sufficiently low molecular weightsuch that a joining temperature far away, e.g. 75° C., from thepolymers' glass transition temperatures does not result.

Overall, polymers of the present disclosure, high molecular weightcopolymers, may be used as an adhesive. These polymers provide greateradhesion strength than existing polymers. Without being bound by theory,polymers of the present disclosure allow improved adhesion to surfacesdue, at least in part, to the increased energy required to promotecohesive removal. Physical entanglement of the polymer adhesive with thepolymers/material of the substrate does not require chemical reaction ofthe polymers with the substrate, unlike known low molecular weightpolymers. In some examples, polymers of the present disclosure arecompatible with epoxies, providing bonding to a thermoset. Polymers ofthe present disclosure provide a high use temperature, but lowprocessing temperature. High use temperature provides for use of thepolymers on components of a vehicle/aircraft. Another application ofpolymers of the present disclosure may be as an adhesive as a diffusionbonded film with a lower processing temperature than typicalthermoplastic and thermoset composites. This allows for joining ofcomposite parts with the use of fewer or no fasteners.

From an assembly perspective, there are multiple benefits with regard tothe use of polymers of the present disclosure. For example, thecomplexity of assembly tooling is improved. In some aspects, polymers ofthe present disclosure have very low flow at elevated temperatures so itis not necessary for a tool to encapsulate the resin, which opens up therange of tooling materials that can be used for a co-bond or post-bondprocess. An elastomeric material can be used to fill tool gaps and allowsome buffer for thermal expansion during a cycle. Thus, a tool with moregenerous tolerances is provided, which significantly reduces tooling andmachining costs. In some aspects, the tooling cost to produce a typicalflight control surface with this method would be in the $30,000 to$50,000 range compared to $500,000 to $1,000,000 for a similar thermosetco-cure tool. Furthermore, in some aspects, adherends do not requireextensive surface preparation that is typically required for adhesivebonding. A simple solvent wipe may be sufficient to obtain a sufficientjoint since melt fusing two polymers of material does not requirecertain functional groups (i.e., physical bonding instead of chemicalbonding) nor is it sensitive to surface energies for wet-out. Thissubstantially or completely eliminates the need for plasma treating ormechanical abrasion processes, which adds savings in both labor andcertification. Furthermore, the vehicle components may be fabricated andcan be inspected for defects prior to joining into an assembly,eliminating costly repairs due to part thinning or dislocation.

While the foregoing is directed to aspects of the present disclosure,other and further aspects of the present disclosure may be devisedwithout departing from the basic scope thereof. Furthermore, while theforegoing is directed to polymers as applied to the aerospace industry,aspects of the present disclosure may be directed to other applicationsnot associated with an aircraft, such as applications in the automotive,marine, energy industry, wind turbine, and the like.

What is claimed is:
 1. A method of forming a polymer, the methodcomprising: A. forming a composition by introducing into a reactor: (1)aluminum chloride, (2) at least one of isophthaloyl chloride orterephthaloyl chloride, (3) an ether ketone ether represented by thestructure:

(4) an ether imide represented by the structure:

wherein each R is independently selected from the group consisting of

wherein each L is independently selected from the group consisting of—CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂— and —CO—, wherein each Q isindependently selected from the group consisting of —S—, —SO₂—,—(CF₃)₂C—, —O—, and —(CH₃)₂C—, and wherein each j is a positive integer;B. mixing the composition; C. introducing a capping agent to thecomposition, wherein the capping agent is selected from the groupconsisting of

benzyl, and combination(s) thereof, wherein R′ is selected from thegroup consisting of hydrogen, halo, C1-C20 alkyl, and cyano; and D.obtaining a polymer.
 2. The method of claim 1, wherein introducing thealuminum chloride into the reactor comprises introducing the aluminumchloride into the reactor at a temperature of about −10° C., followed byallowing a temperature of the composition to increase to about 10° C.,followed by cooling the composition to a temperature of about −10° C. 3.The method of claim 1, further comprising introducing a solvent into thereactor, wherein the composition comprises the solvent.
 4. The method ofclaim 3, wherein the solvent is selected from the group consisting ofo-dichlorobenzene, dichloromethane, dichloroethane, and mixture(s)thereof.
 5. The method of claim 3, wherein introducing the solvent isperformed by preheating the solvent before introducing the solvent intothe reactor.
 6. The method of claim 5, wherein preheating is performedat a temperature of from about 160° C. to about 190° C.
 7. The method ofclaim 1, wherein mixing is performed at a temperature of from about −30°C. to about 25° C.
 8. The method of claim 1, wherein obtaining thepolymer comprises introducing water and ammonia to the composition. 9.The method of claim 1, wherein the polymer comprises: (1) at least oneof

wherein each R of the polymer is independently selected from the groupconsisting of

wherein each L of the polymer is independently selected from the groupconsisting of —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂— and —CO—, wherein each Qof the polymer is independently selected from the group consisting of—S—, —SO₂—, —(CF₃)₂C—, —O—, and —(CH₃)₂C—, and wherein each j of thepolymer is a positive integer; and (4) a capping agent selected from thegroup consisting of

and benzyl, wherein R′ of the polymer is selected from the groupconsisting of hydrogen, halo, C1-C20 alkyl, and cyano, wherein themolecular weight of the polymer is from about 50 kDa to about 150 kDa.10. The method of claim 9, wherein the molecular weight of the polymeris from about 90 kDa to about 110 kDa.
 11. The method of claim 9,wherein the polymer is a random copolymer.
 12. The method of claim 9,wherein the polymer is a block copolymer.
 13. A method for forming abonded prepreg stack, the method comprising: A. coating a thermoplasticprepreg with a polymer to form a coated thermoplastic prepreg, and B.introducing the coated thermoplastic prepreg to an adherend, wherein thepolymer comprises: (1) at least one of

(2)

or (3)

wherein each R is independently selected from the group consisting of

wherein each L is independently selected from the group consisting of—CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂— and —CO—, wherein each Q isindependently selected from the group consisting of —S—, —SO₂—,—(CF₃)₂C—, —O—, and —(CH₃)₂C—, and wherein each j is a positive integer;and (4) a capping agent selected from the group consisting of

and benzyl, wherein R′ is selected from the group consisting ofhydrogen, halo, C1-C20 alkyl, and cyano, wherein the molecular weight ofthe polymer is from about 50 kDa to about 150 kDa.
 14. The method ofclaim 13, wherein the molecular weight of the polymer is from about 90kDa to about 110 kDa.
 15. The method of claim 13, wherein the polymer isa random copolymer.
 16. The method of claim 13, wherein the polymer is ablock copolymer.
 17. The method of claim 13, wherein the adherend isselected from the group consisting of a thermoset composite, athermoplastic composite, a metal substrate, and combination(s) thereof.18. The method of claim 13, further comprising heating the coatedthermoplastic prepreg and adherend to form the bonded prepreg stack. 19.A method for forming a bonded prepreg stack, the method comprising:coating an adherend with a polymer to form a coated adherend, andintroducing the coated adherend to a thermoplastic prepreg, wherein thepolymer comprises: (1) at least one of

(2)

or (3)

wherein each R is independently selected from the group consisting of

and wherein each L is independently selected from the group consistingof —CH₂—, —(CH₃)₂C—, —O—, —S—, —SO₂— and —CO—, wherein each Q isindependently selected from the group consisting of —S—, —SO₂—,—(CF₃)₂C—, —O—, and —(CH₃)₂C—, and wherein each j is a positive integer;and (4) a capping agent selected from the group consisting of

and benzyl, wherein R′ is selected from the group consisting ofhydrogen, halo, C1-C20 alkyl, and cyano, wherein the molecular weight ofthe polymer is from about 50 kDa to about 150 kDa.
 20. The method ofclaim 19, wherein the molecular weight of the polymer is from about 90kDa to about 110 kDa.
 21. The method of claim 19, wherein the polymer isa random copolymer.
 22. The method of claim 19, wherein the polymer is ablock copolymer.
 23. The method of claim 19, wherein the adherend isselected from the group consisting of a thermoset composite, athermoplastic composite, a metal substrate, and combination(s) thereof.24. The method of claim 19, further comprising heating the coatedadherend and the thermoplastic prepreg to form the bonded prepreg stack.25. The method of claim 19, wherein each R is independently selectedfrom the group consisting of: